Constant-speed film-feeding mechanism



July 2, 1935. A. POULSEN ,7

' CONSTANT SPEED FILM FEEDING MECHANISM I Filed Au 19, 1931 Z 71i/e77f0/i: Arno 2i PouZqe 7z iatented July 2, 1935 UNITED STATES (DONSTAN'EE'SPEED FILM-FEEDING Ii/MECHANISM Arnold Poulsen, Heller-up, Copenhagen, Denmark, assignor of part interest to Axel Carl Georg ifetersen, Copenhagen, Denmark Application August 19, 1931, Serial No. 558,159 in Germany September 1, 1930 Claims. (or err-2.3)

mounted on'the fly-wheel shaft, or, finally, an

in the recording of sound waves on a moving film and in the reproduction of sounds, which are recorded on a film, it. has previously been proposed to maintain a constant speed of movement of the film during the recording or reproduction by means of a fiy-wheel, which is in driving connection with the film.

order to avoid the rate of velocity of the fly-wheel exceeding a certain limit, it has further been proposed to apply a brake, hich is intermittently coupled to the driving me hanism of the fly-wheel, when the speed of revolution of same increases beyond a predetermined value.

It has also been proposed to apply a brake which constantly counteracts the movements of the film and is coupled to a separate roller over which the film is passed. This brake serves the purpose of keeping tightened the portion of the illmtravelling through a sound gate located between the said roller and the point where the fiy-wheel is in driving connection with the film. The friction between the sound gate and the film acts upon the said portion-of the film as a braking eifect, which varies as the speed of the film varies and, consequently, should to some degree compensate irregularities in the motion of the dim caused by irregularities in the driving effect. in practice, however, this compensation is very incomple because the said friction efic'ect, due to the presence of dust, etc., in the gate, is not imiform even it the speed of the film is constant.

The present invention relates to systems for maintaining constant the speed of movement of a somid film by means of' a fiy-wheel in which the motion of the film is constantly counteracted by a brake and according to the invention the retarding effect produced by the said brake is utilized for the purpose of suppressing periodic vibrations of the fiy-wheel and the portionnf the film travelling towards the point of illumination without the utilization for the said purpose of any friction in a sound gate. To this end the point oi illumination of the film is in well-known manner situated at the periphery of a rotary filmdriven roller over which the film is passed wherefore the invention is limited to systems in which this arrangement appears-and according to the invention the brake is coupled either to the last mentioned roller or to a separate roller, which is driven by the passage or the film over I same and engages the portion of the dim travelling onto the tower roller. v

The brake device may be an ordinary friction brake, a rotary air or oil-brake, for example a tan rotating in air or oil, or one ormore tans eddy-current brake.

For the purpose of bringing out more clearly the distinguishing feature or the-present invention, reference will be made in the following description to devices illustrated in the accompanying drawing wherein:

Figure 1 shows, in elevation, a speed regulating device, according to the prior art, in which the ily-wheel is driven by the film and coupled to the roller at the periphery of which the point of illumination of the iilm is situated.

Fig. 2 shows in elevation a form of construction or a speed-regulating deviceconstructed in accordance with the present invention.

a is a film and b is a fly-wheel coupled to a roller c around which the film a passes. The film is moved in the known manner by toothed sprockets d and d in the direction indicated by the arrows.

in the constructions shown in Fig. i, an inter-'- mediate member 1 of known type and actuated by aspring e is used, for equalizing the variations in the speed at which the film is driven by the driving sprocket dl. It desired several intermediate members of this type may be used.

The film is illuminated at the sound control sage of the film a over the roller 0, but if desired the fiy-wheel may be coupled to the driving mechanism, which drives the sprockets d and d by means of a proper resilient clutch.

In the construction shown in Fig. 2 in which the ily-wheel, by way of example, is also assumed to be driven by the dim, the point g at which the film isilluminated. for recording and reproducing purposes is situated at the periphery of a separate roller 1' and is pressed against this roller by means of rollers it. From the roller 1' the film passes around a guide roller v and then around the roller 0. The brake 31,11, t, s produces a braking action, which replaces the triotion set up by the passage of the film through the sound gate in the above-mentioned known construction, and the brakingaction is adjusted in such a manner that it 'restrains periodical oscillations of the system comprising the flywheel and the portion or thefilm travelling towards same.

As stated above, the brake p, q may be replaced by braking devices of various other constructlons.

. dependent of said motor, the length of film be- I Instead of connecting the brake may to a 'separate roller 1', the brake may be connected to the fiy-wheel shaft itself or, what amounts to, the

' same thing, to the shaft of the roller 0 in Fig. 1.

independent of said motor, and a brake restralning said roller.

2. Mechanism for feeding a sound film past a light beam comprising two toothed sprockets for propelling the film, a motor for driving said sprockets; between said sprockets a drum, a roller mounted on said drum, and a flywheel, said roller and flywheel being driven by the'film and intween' said sprockets being free of frictional restraint; and a brake engaging said drum.

3. A mechanism for feeding a sound film past a light beam comprising toothed prockets for propelling the film; a motor for driving said sprockets; a drum, at the'periphery of which the 'ffilm passes the said beam of light; a fiy-wheel and a continuously working brake, both of which are coupled to said drum so as to be driven together with the latter independent of the said motor by the, passage of the film over said drum. 4. A mechanism accordingto claim -3 and in which the brake is applied direct to the drum and the fiy wheel is coupled to said drum through the agency of the film.

5. Mechanism for feeding a film past a light beam comprising feeding means and take-up means for propelling the film, a motor for operating said means, a film-supporting roller and a separate flywheel between said film-propelling means; the roller and fiywheel being driven bythe film independently of the motor, and a brake 2o restraining said roller.

' ARNOLD POULSEN. 

